The FBI is operating a small air force across the U.S. with scores of low-flying planes carrying video and, at times, cellphone surveillance technology — all hidden behind fictitious companies that are fronts for the government, The Associated Press has learned.

The planes’ surveillance equipment is generally used without a judge’s approval, and the FBI said the flights are used for specific, ongoing investigations. In a recent 30-day period, agency planes flew above more than 30 cities in 11 states across the country, an AP review found.